[Scan-DC] Montgomery FD Radio Callsigns for Metro Incidents

[Jeff Krauss]

Listening to a smoking insulator incident this morning at the 
Friendship Metro Station on TG 7G.
I heard Rail 702, who apparently is a Metro employee; and Rail 708, 
who apparently is the officer of Engine 719.
I also heard NCR 700 and NCR 702, who are apparently part of some 
supplementary communications team.
I think NCR refers to the National Capital Region Radio Cache.
http://www.interoperability.virginia.gov/pdfs/NCR_Radio_Cache_Deploym_Procs.pdf
Can anyone elaborate on the callsigns and responsibilities of these folks?